Each municipality operating under a five-member or six-member city council form of government shall hold municipal elections to fill, for a term of four years, the following offices in the following years:
(1) in the year following a year in which a presidential election is held, the offices of:
(a) approximately half the council members; and
(b) except as provided in Subsection (2)(b), mayor; and
(2) in the year preceding a year in which a presidential election is held, the offices of:
(a) the remaining council members; and
(b) for a municipality that elected a mayor in 2015 for a term of four years, mayor.